Synthesis And Electrochemical Perfrmance Of Li₄Ti₅O₁₂ As The Negative Materials For Lithium Ion Batteries

Spinel Li4Ti5O12is a promising lithium ion battery anode material. It has some evident advantages:there is negligible volume change during charge/discharge process （the so-called "zero-strain insertion material"）, so it possesses excellent reversibility; its Li-insertion potential is at about1.55V vs. Li+/Li, which is high than the reduction voltage of common electrolyte; the diffusion coefficient is2×10-11cm2/s, so it has excellent lithium ion mobility that promising for high-rate battery applications. Furthermore, this material accommodates Li+with theoretical capacity of175mAh/g. Compared with graphite anode material, Li4Ti5O12is considered to be of better rate performance and safety.In this text, Materials for lithium ion batteries was synthesized through a simple solid state reaction in an inert atmosphere using yttria as Y3+dopant source and sucrose or conductive carbon black as carbon source. Composites were characterized by XRD, SEM analysis combined with electrochemical tests, and the effects of Y3+doping, Y3+and carbon doped simultaneously, and different carbon sources such as sucrose or conductive carbon black on the morphology, particle size, electrochemical and performance of anode materials were investigated. It shows that Li（4-x/3）YxTi（5₂x/3）O12（x=0.1） composites using yttria as Y3+dopant source and sucrose as carbon source exhibited a relatively good rate capability and cycling stability. At the charge-discharge rate of0.15C,0.4C,0.7C,1.4C and3.3C, its discharge capacities were149.0,144.5,144.5,141.3and118mAh/g, respectively. After10cycles at3.3C, its discharge capacity remained at115.0mAh/g. The impedance Rct of this material is227.7Ω, while that of the undoped Li4Ti5O12material is912.5Ω.